Abstract:
Chlamydia pneumoniae is a gram-negative bacteria which causes both upper and lower respiratory tract infections. It has also been reported to be associated with atherosclerotic heart disease, asthma, inflammatory arthritis, Alzheimer’s disease and several other chronic diseases which represent significant health problems in many countries. C. pneumoniae can cause persistent infections with and without symptoms, then it is difficult to interpret between the healthy carriers from upper respiratory tracts infections. Diagnosis and treatment is necessary for cases with acute or chronic upper respiratory tract infections to prevent a progression of the diseases to more severe forms. The study employed direct immunofluorescence (DIF) to detect C. pneumoniae from nasopharyngeal swabs in order to assess the diagnosis of upper respiratory tracts infections (URI) by C. pneumoniae. Nasopharyngeal swabs were collected from 33 patients with clinical manifestation of upper respiratory tracts infections as well as from a 16 healthy individuals.
Monoclonal antibody against C. pneumoniae (TW183) and rabbit anti-mouse immunoglobulinG-FITC were used as primary and secondary antibodies in DIF. C. pneumoniae was detected in 31 of 36 (86.1%) of patient specimens. Of the 36 samples, 29 of 36 (80.5%) were URI with pharyngitis, cough and/or mild fever, 6 cases (16.7%) were sinusitis and 1 case (2.8%) was URI with asthma. C. pneumoniae was undetectable in all 16 healthy subjects. When comparing the developed DIF to antibodies detection data by microimmunofluorescence (MIF) provided by the National Institute of Health, Department of Medical Science, a significant correlation was found between DIF and MIF in interpretation of C. pneumoniae infections (McNemar Chi-square’s test, p>0.05). Although C. pneumoniae could be detected in 8 cases by DIF with antibodies undetectable by MIF, antibodies against C. pneumoniae were detected 1 or 2 months later in 3 samples from 2 patients with the consistent pathogen detectable from nasopharyngeal swabs. Therefore DIF is valuable for use in combination with antibodies detection by MIF for accurate diagnosis of C. pneumoniae infections and could be an alternative test which is superior for earlier diagnosis of C. pneumoniae infections.